3-Aminopyridine → N-3-Pyridinylurea

Participants

Reaction Conditions

Reaction Steps

Benzoyl isocyanate (3.28 g, 22.3 mmol, 1.05 equiv.) was taken up in CH2Cl2 (30 mL) and cooled to −10° C. Pyridin-3-amine (2 g, 21.2 mmol, 1 equiv.) was added in portions while stirring. The mixture was allowed to stir for 3 h at room temperature. After the reaction was deemed complete, it was concentrated and then taken up in a 1:1 mixture of CH3OH and H2O (100 mL) followed by the addition of NaOH (4.25 g, 106.3 mmol, 5 equiv.). The reaction was allowed to stir overnight at room temperature, concentrated to dryness, and then azeotroped three times with toluene. A mixture of 10% CH3OH in EtOAc (100 mL) was added to the solid and stirred for 10 minutes followed by filtration. The solid was suspended and filtered two additional times. The combined filtrates were filtered once more to remove any solids that passed through the filter and concentrated. The residue was triturated with EtOAc (5 mL) and dried under vacuum to yield 3.5 g of crude material (off-white solid) that was utilized without further purification. LC/MS: m/z (ES+) 138 (M+H)+.

Provenance & Evidence